Within this class of models, analysts must make several choices about the structure of the specific model to be adopted. First, it must be decided how exactly the non-terminal event time \(T_1\)  affects \(h_{03}(t_2|t_1)\)  in submodel (). The so-called Markov structure sets \(h_{03}(t_2|t_1) = h_{03}(t_2)\) , meaning the baseline hazard is independent of \(t_1\) . Alternatively, the semi-Markov structure sets \(h_{03}(t_2|t_1) = h_{03}(t_2-t_1)\) , so the time scale for \(h_3\)  becomes the time from the non-terminal event to the terminal event (sometimes called the sojourn time) [1]}, [2]}. Semi-Markov specification also allows functions of \(t_1\)  as covariates in the \(h_3\)  submodel, to further capture dependence between \(T_1\)  and \(T_2\) .
